Alchichica silverside

<em>Poblana alchichica</em> is a freshwater silverside of the family Atherinopsidae, endemic to the ancient crater lake of Alchichica in the state of Puebla, Mexico. No maximum length or weight data are currently available in the scientific literature for this species. As a member of the New World silversides, <em>P. alchichica</em> is likely a small, slender, schooling fish adapted to the alkaline, saline conditions of its volcanic lake habitat—a chemically extreme environment that supports a highly specialized endemic fauna. Lake Alchichica is a maar lake of exceptional ecological interest, and the silversides endemic to it represent a remarkable example of isolation and adaptation within a confined freshwater system. The genus <em>Poblana</em> is restricted to a small number of Mexican crater lakes, and species within it face significant conservation pressure due to the limited size of their habitats. Details of habitat and range for this species remain limited in the ichthyological literature. Its formal conservation status has not been evaluated, though the lake-endemic nature of this fish makes it inherently vulnerable to environmental change.